Method and device for conveying folded sheet elements

ABSTRACT

A method and device for conveying folded sheet elements, whereby a sheet element, folded to have at least two superimposed portions connected along a fold, is fed along a given path by a movable gripping head, which engages and retains by suction a first of the two portions of the sheet element, and simultaneously deforms the fold to retain the second portion in contact with the first as the sheet element is conveyed.

[0001] The present invention relates to a method of conveying foldedsheet elements.

[0002] The present invention may be used to advantage in the tobaccoindustry to supply a line for packing tobacco products, in particularcigarettes, with sheet elements defined by folded coupons, to which thefollowing description refers purely by way of example.

BACKGROUND OF THE INVENTION

[0003] On some packing lines in the tobacco industry, each packet ofcigarettes produced or being produced on the line is provided with acoupon, which at times is folded to form at least two superimposedportions connected along a fold.

[0004] Single-sheet coupons, i.e. defined by a nonfolded sheet element,are normally supplied to a packing line by means of a conveying member,which retains the coupons by suction and feeds them on to the linesuccessively.

[0005] When dealing with folded coupons, however, such a conveyingmethod, though cheap and easy to implement, poses several drawbacks, bythe conveying member only engaging one of the folded portions of thecoupon by suction, while the other/s, not being position controlled inany way, are allowed to “flap” freely and detach from the portionretained by suction.

SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide a conveyingmethod enabling even folded sheet elements to be conveyed safety bysuction.

[0007] According to the present invention, there is provided a method ofconveying sheet elements folded to comprise at least two superimposedportions connected along a fold; the method comprising the steps ofengaging a first of said two portions of said sheet element by means ofsuction conveying means; deforming said first portion and said fold toretain a second of said portions in contact with said first portion;retaining said sheet element with said first portion and said folddeformed, and with said first portion in contact with the suctionconveying means; and moving said suction conveying means along a givenpath.

[0008] The present invention also relates to a device for conveyingfolded sheet elements.

[0009] According to the present invention, there is provided a devicefor conveying sheet elements folded to comprise at least twosuperimposed portions connected along a fold; the device comprisingmovable conveying means having a suction surface for engaging a first ofthe two said portions; said suction surface retaining said first portionby suction, and being designed to simultaneously deform said fold toretain a second of said portions in contact with said first portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will be described with reference to theaccompanying drawings, in which:

[0011]FIG. 1 shows a schematic, three-quarter underside view inperspective of a preferred non-limiting embodiment;

[0012]FIG. 2 shows a view in perspective of a second embodiment of adetail in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Number 1 in FIG. 1 indicates as a whole a device for conveyingand feeding a coupon 2 to a known cigarette packing line 3.

[0014] In the example shown, coupon 2 is fan-folded, and comprises afirst pair 4 of superimposed portions 5 and 6 connected to each otheralong a fold 7; and a second pair 8 of superimposed portions 9 and 10connected to each other along a fold 11 parallel to fold 7. Portions 6and 9 are also connected to each other along a fold 12 parallel to andopposite folds 7 and 11.

[0015] Device 1 comprises a transfer unit 13, in turn comprising a slide14 powered in known manner (not shown) to run back and forth, along aguide 15 and in a direction 15 a which, in the example shown, issubstantially horizontal, between a pickup station 16, to pick up acoupon 2, and a feed station 17, to feed coupon 2 to packing line 3.Transfer unit 13 also comprises a telescopic actuator 18 suspended fromslide 14 and fitted on its bottom free end with a gripping head 19,which is defined at the bottom by a suction surface 20 facing a grippingposition 21 of pickup station 16, and is moved by actuator 18 to andfrom gripping position 21 in a direction 22 which, in the example shown,is substantially vertical.

[0016] Surface 20 is a cylindrical curved surface (concave in theexample shown) with generating lines parallel to direction 15 a, andfaces a cylindrical curved surface 23 (concave in the example shown),complementary to surface 20 and with generating lines parallel todirection 15 a, of an anvil 24, which is located on the opposite side ofpickup station 16 with respect to transfer unit 13, and is moved to andfrom gripping position 21 in direction 22 by a telescopic actuator 25which is substantially coaxial with actuator 18 when transfer unit 13 isat pickup station 16.

[0017] In a variation not shown, anvil 24 has no actuator 25, and isfixed at gripping position 21.

[0018] Device 1 also comprises a guide 26 extending, parallel todirection 15 a, between pickup station 16 and feed station 17, and whichis coplanar with gripping position 21 and comprises two channel sections27 positioned with their concavities facing each other, and separated bya distance substantially equal to the length of folds 7, 11 and 12.

[0019] Finally, device 1 comprises a feed device 28 for feeding coupons2 to pickup station 16. In the example shown, device 28 is a knowngripper-type feed device, which moves to and from pickup station 16 in adirection 29 perpendicular to directions 15 a and 22, to feed eachcoupon 2 to gripping position 21 with folds 7, 11 and 12 extendingcrosswise to the generating lines of surfaces 20 and 23.

[0020] In actual use, when a coupon 2, positioned with folds 7, 11 and12 parallel to direction 29, is fed by feed device 28 to grippingposition 21, transfer unit 13 is located at pickup station 16, andgripping head 19 and anvil 24 are raised and lowered respectively withrespect to gripping position 21. Gripping head 19 and anvil 24 are thenmoved towards each other to grip coupon 2 between surfaces 20 and 23,which, cooperating with each other, curve folds 7, 11 and 12, which are“frozen” in this curved position by activating suction through surface20. The suction, in fact, by acting directly on at least portion 5 andfold 7 of coupon 2, itself keeps these two elements in the curvedposition even without anvil 24. Maintaining a curved fold 7 also keepsportion 6 and fold 12 curved, so that portions 9 and 10 and fold 11 arealso maintained curved and so adhere to portions 5 and 6 even withoutanvil 24.

[0021] At this point, anvil 24 can be lowered and the slide moved indirection 15 a to feed coupon 2 along guide 26 to feed station 17. Inthe course of this movement, any lateral portions of coupon 2 projectingcrosswise to direction 15 a from gripping head 19 engage the inside ofrespective sections 27, which may even be dispensed with and servesolely to prevent coupons 2 from dropping in the event suction is cutoff, and possibly also to center coupons 2 with respect to gripping head19.

[0022] As will be clear from the foregoing description, to engage afolded sheet element by suction along at least one fold and convey thesheet element, without flapping, along a given path, the fold must bemaintained curved as the element is conveyed. And when dealing withmultiple parallel folds, as in the example shown, all the folds mustobviously be maintained curved as the element is conveyed.

[0023] Though, in the example shown, surface 20 is concave and surface23 convex, the same result would obviously be achieved even with aconvex surface 20 and a concave surface 23. Surface 20 may also have anyshaped curve, or even be undulated.

[0024] In the FIG. 2 example, surface 20 of gripping head 19, whensectioned crosswise to direction 15 a, is substantially V-shaped anddefined by two flat portions 20″ and 20′″ connected by a rib 20′.

[0025] As will be clear from the foregoing description, once folds 7, 11and 12 are all curved by the opposite pressures exerted by gripping head19 and anvil 24, the suction through surface 20, by acting directly onportion 5 and fold 7, is sufficient to keep all folds 7, 11 and 12curved, so that portions 5, 6, 9 and 10 all adhere to one another and tosurface 20. When dealing with a coupon only comprising portions 5 and 6and fold 7, however, gripping head 19 is obviously perfectly capable ofcurving portion 5 and fold 7, and therefore also portion 6, by suctionalone. Consequently, to convey by suction a sheet element simply foldedinto two along one fold, anvil 24 may be dispensed with or replaced, ifnecessary, by a straightforward fixed flat supporting plate defininggripping position 21.

[0026] The same also applies when conveying by suction a sheet elementfolded into four along two parallel, superimposed first folds and afurther intermediate fold crosswise to the other two. In which case, theintermediate fold need simply be curved directly by suction, so that allthe portions of the sheet element adhere to the portion of the sheetelement contacting gripping head 19 and subjected to suction.

[0027] To convey a sheet element folded along three or more foldsforming an angle, surfaces 20 and 23 must be complementary and have, asopposed to a single curve as in the example shown, a double curve so asto curve all the folds in the sheet element to be conveyed.

1) A method of conveying sheet elements folded to comprise at least twosuperimposed portions (5, 6) connected along a fold (7); the methodcomprising the steps of engaging a first (5) of said two portions (5, 6)of said sheet element (2) by means of suction conveying means (19);deforming said first portion (5) and said fold (7) to retain a second(6) of said portions (5, 6) in contact with said first portion (5);retaining said sheet element (2) with said first portion (5) and saidfold (7) deformed, and with said first portion (5) in contact with thesuction conveying means (19); and moving said suction conveying means(19) along a given path. 2) A method as claimed in claim 1,characterized in that said step of deforming said first portion (5) andsaid fold (7) is performed by bringing the first portion (5) and thefold (7) into contact with a surface (20) carried by said suctionconveying means (19). 3) A method as claimed in claim 2, characterizedin that said surface (20) has a curved section when sectioned in a planeparallel to said fold (7) and crosswise to the folded said sheet element(2). 4) A method as claimed in claim 2, characterized in that saidsurface (20) has a substantially V-shaped section when sectioned in aplane parallel to said fold (7) and crosswise to the folded said sheetelement (2). 5) A method as claimed in claim 2, characterized in thatsaid surface (20) is a suction surface. 6) A method as claimed in claim1, characterized in that said sheet element (2) comprises a number ofsuperimposed portions (5, 6, 9, 10) and at least two parallel folds (7,11); said step of deforming said first portion (5) and said folds (7,11) being performed by pushing the first portion (5) and the folds (7,11) into contact with a surface (20) carried by said suction conveyingmeans (19), so that said surface (20) cooperates, with the interpositionof the folded said sheet element (2), with a complementary surface (23)carried by opposing means. 7) A device for conveying sheet elementsfolded to comprise at least two superimposed portions (5, 6) connectedalong a fold (7); the device comprising movable conveying means (19)having a suction surface (20) for engaging a first (5) of the two saidportions (5, 6); said suction surface (20) retaining said first portion(5) by suction, and being designed to simultaneously deform said fold(7) to retain a second (6) of said portions (5, 6) in contact with saidfirst portion (5). 8) A device as claimed in claim 7, characterized bycomprising feed means (28) for feeding said sheet element (2), with agiven orientation, to a gripping position (21) of a pickup station (16)where the sheet element (2) is picked up by said movable conveying means(19); said surface (20) having a curved section when sectioned in aplane parallel to said fold (7) and crosswise to the folded said sheetelement (2) positioned with said orientation at said gripping position(21). 9) A device as claimed in claim 7, characterized by comprisingfeed means (28) for feeding said sheet element (2), with a givenorientation, to a gripping position (21) of a pickup station (16) wherethe sheet element (2) is picked up by said movable conveying means (19);said surface (20) having a substantially V-shaped section when sectionedin a plane parallel to said fold (7) and crosswise to the folded saidsheet element (2) positioned with said orientation at said grippingposition (21). 10) A device as claimed in claim 8, characterized in thatsaid surface (20) is a suction surface (20). 11) A device as claimed inclaim 8, for conveying sheet elements (2) comprising a number ofsuperimposed portions (5, 6, 9, 10) and at least two parallel folds (7,11); the device being characterized by comprising opposing means (24)having an opposing surface (23) complementary to said suction surface(20) and facing the suction surface (20); said opposing surface (23) andsaid suction surface (20) being movable with respect to each other togrip a said sheet element (2) and deform said portions (5, 6, 9, 10) andsaid folds (7, 11).